Well, they didn't get off entirely scot-free. Five of the Teamsters--tracked down by patient effort from the videotapes, with NO help from the police or Teamster Local 115--pled guilty in exchange for negligible probation sentences. No trials, no details potentially embarrassing to the Teamsters or to Rendell, no media, no muss, no fuss.
Johnny Morris, the ringleader, was never prosecuted, but he suffered a worse fate: the beating incident was one of the motivations for a raid on Local 115 by the union itself, which resulted in Morris losing the local he built, and ultimately being drummed out of the Teamsters. He died earlier this year, still attempting to win his position back. The events reportedly took a very heavy toll on him.